Rope through winch

Description

[0001] The present invention relates to a rope-through winch with a drive unit and a driven unit for applying a driving force to a rope, which is coupled to the drive unit.

[0002] Winches in general have been known for a long time and are used in all sectors of industry for lifting loads and people, especially for bridging differences in height. One specific type of winch is the so-called rope-through winch, in which the rope is fed through the winch instead of being wound onto it, for example, in a drum. The rope can hang down on one or both sides of the rope-through winch due to gravity or an applied load, so that the winch does not need to store the portion of the rope that passes through it. This allows rope-through winches to have an unlimited lifting or pulling length. Such rope-through winches are particularly useful when an infrastructure for attaching external winches is already in place, or can be provided, in a hoisting shaft or on a building.

[0003] Rope-driven winches are typically used for transporting people and materials, for example in window cleaning gondolas.

[0004] For example, alternating current motors are used as drives in rope-through winches, which can be connected to a power supply network via a connector.

[0005] These cable-driven winch designs typically have the disadvantage that voltage dips in the power grid directly affect the drive unit, potentially causing the winch to enter an unstable operating point. This operating characteristic means that cable-driven winches are only of limited use in countries with poor power supplies.

[0006] US 2015 / 090946 A1 discloses a chain hoist with speed control. The chain hoist includes a user control for changing the hoist's speed, integrated into a handheld control unit. The handheld control unit includes a potentiometer for adjusting the output voltage of a frequency converter.

[0007] US 2003 / 0098668 A1 relates to a variable speed drive which has a converter by means of which an alternating current supplied by a power source is converted into a direct current and back into an alternating current before being delivered to the motor.

[0008] EP 0 347 408 A1 describes a drive for a hoist with a mains-powered three-phase motor. A frequency converter is assigned to the three-phase motor. To limit the motor speed and thus prevent overspeeding when lowering a load, the motor current consumption and frequency are monitored.

[0009] A rope-through winch according to the preamble of claim 1 is known from DE 20 2011 106 995 U1.

[0010] Against this background, the present invention was based on the objective of creating a rope-through winch which mitigates the disadvantages described above as much as possible, and in particular to enable a rope-through winch for countries with poor electricity supply.

[0011] The invention solves the underlying problem in a rope-through winch of the type described above with the features according to claim 1.

[0012] Accordingly, a rope-through winch is proposed with a drive unit and a driven unit for applying a driving force to a rope, which is coupled to the drive unit, wherein the drive unit comprises: a frequency converter with a primary side for drawing current from a supply network and a secondary side for supplying an alternating voltage, an alternating current motor for driving the rope-through winch at variable speed, which is supplied with the alternating voltage by the frequency converter, and a control unit which is connected to the frequency converter and the alternating current motor for controlling the drive unit, wherein the control unit is connected to the alternating current motor via a forward conductor and a return conductor and is configured to change the speed of the alternating current motor by means of the frequency converter.In particular, it is proposed according to the invention that the rope-through winch has a control unit and a frequency converter which are configured to change the speed of the AC motor by means of the frequency converter.

[0013] The invention utilizes the fact that lifting devices and traction equipment exhibit a substantially constant load during operation, and therefore the drive power is essentially a function of the rotational speed. In particular, the invention takes advantage of the fact that, in lifting devices, only the load to be lifted determines the required lifting force, and therefore, when the supply voltage drops, i.e., when the mains voltage drops, the speed, i.e., the rotational speed of the AC motor, is reduced to counteract the effect of the voltage drop.

[0014] Preferably, the control unit includes means for voltage detection and is configured to change, in particular reduce, the speed of the AC motor when an undervoltage is detected. The control unit thus includes at least one device for detecting a voltage, in particular a voltmeter, which is designed to detect voltages, preferably on the primary side of the frequency converter, and transmit these to the control unit. The control unit itself is further configured to compare the detected voltages with pre-programmed voltage limits and, in the event of a lower limit being undershot, a so-called undervoltage, to adjust the speed of the AC motor so that the mechanical power of the AC motor corresponds to the electrical power supplied by the mains supply.The control unit is therefore prepared to throttle the AC motor, in particular to reduce the speed of the AC motor.

[0015] According to a preferred embodiment of the invention, the control unit of the rope-driven winch includes current sensing means, wherein the control unit is configured to change, in particular reduce, the speed of the AC motor upon detection of an overcurrent. Preferably, the current sensing means are designed as overcurrent protection, which is configured to detect a rated current on the secondary side of the frequency converter and to transmit the detected rated current to the control unit. The control unit further includes pre-programmed current limits and is configured to compare the detected currents with the pre-programmed current limits and, in the event of an upper limit being exceeded, a so-called overcurrent, to adjust the speed of the AC motor so that the mechanical power of the AC motor corresponds to the electrical power supplied by the power grid.to protect the AC motor from a critical operating current.

[0016] Currents and voltages can be measured in both single-phase and multi-phase modes.

[0017] Optionally, the control unit of the cable winch is configured to change the speed of the AC motor in steps, preferably between four, and more preferably between two steps. For this purpose, the control unit includes, for example, a switching device configured to change the excitation voltage of the AC motor in steps, particularly so that the AC motor can also change its direction of rotation. Preferably, the AC motor can be operated at least in a first and a second speed in a forward direction of rotation, as well as at least one reverse direction. The steps are therefore preferably selectable depending on the direction of rotation and the speed.

[0018] According to a further preferred embodiment of the invention, the control unit comprises a control database, wherein the control database is configured to provide pre-programmed control values ​​to the control unit, in particular depending on detected voltages. The control database of the control unit is preferably configured to store control values ​​according to the installation location or the corresponding supply network, so that the cable winch can operate on a wide variety of supply networks. Such an embodiment is particularly advantageous for mass production, since the cable winches can be manufactured independently of their installation location and programmed on-site according to the installation location.

[0019] Preferably, the control unit of the rope-driven winch is configured to adjust the speed of the AC motor, depending on the detected undervoltage and / or overcurrent, upon detection of an undervoltage by the voltage sensing means and / or an overcurrent by the current sensing means. This adjustment ensures that the electrical power consumption of the AC motor decreases by the same amount as the AC voltage supplied by the mains to the frequency converter. For this purpose, the control unit compares the detected current or voltage with pre-programmed setpoint values. In the event of a deviation, the motor is switched to a corresponding stage so that the electrical and mechanical torques are essentially equal. This prevents, in particular, runaway winches and / or overcurrents in the AC motor.

[0020] According to a further preferred embodiment of the invention, the control unit of the rope-driven winch is configured to halve and double the electrical power requirement of the AC motor. Preferably, the AC motor is controlled in stages that are multiples of each other. A particular advantage here is that this can be implemented simply, for example, by resistor bridge circuits or simple switching operations, thus avoiding overly complex control, as would be the case, for example, with continuous control of an AC motor.

[0021] According to a further preferred embodiment of the invention, the frequency converter of the rope-driven winch is configured to operate on a power supply network with a number of phases, preferably in the range of one to three phases. For this purpose, the AC motor is designed, for example, as a 1-phase or 3-phase motor, so that it can be operated on both a single-phase and a three-phase power supply network.

[0022] According to a particularly preferred embodiment, the frequency converter and the control unit of the rope-feed winch are designed as an integrated device. A particularly advantageous feature of an integrated, especially one-piece, design is the resulting modular construction, which allows for easy retrofitting of existing AC motors in rope-feed winches.

[0023] According to a particularly preferred embodiment of the invention, the power supply network to which the rope-driven winch is connected has a nominal voltage of at least 50 V, preferably at least 100 V, more preferably at least 200 V, and particularly preferably at least 230 V. The rope-driven winch is therefore designed to operate even on a lower-voltage power supply network, such as 50 V. Preferably, the rope-driven winch is operated on power supply networks with a nominal voltage of 200 V to 400 V.

[0024] According to a further preferred embodiment of the invention, the AC motor of the cable winch is designed for operation with a single-phase nominal AC voltage of 230 V. The AC motor is therefore designed as a 1-phase 230 V AC motor. The high availability of spare parts and the ease of maintenance of such AC motors are particularly advantageous. This is especially important in countries with poor infrastructure, which typically also have a largely unstable power grid.

[0025] According to a further preferred embodiment of the invention, the frequency converter of the rope-driven winch is configured for operation on a three-phase power supply network with at least 400 V. The rope-driven winch is therefore also suitable for use in Europe.

[0026] According to a further preferred embodiment of the invention, the control voltage of the rectifier is 24 V, preferably 230 V. The cable winch is therefore switched using a control voltage of 24 V or 230 V. However, other control potentials would also be conceivable.

[0027] According to a further preferred embodiment of the invention, the rope-feed winch has an adapter with a mains-side primary side and a secondary side for connection to the rope-feed winch, wherein the adapter is configured to provide at least a single-phase nominal AC voltage of 230 V on the secondary side. For connecting the rope-feed winch to the supply network, for example, an adapter can be used which is configured to electrically couple the rope-feed winch to a supply network. Preferably, the adapter provides the frequency converter with a single-phase AC voltage of 230 V. A particular advantage here is that the rope-feed winch can be configured at low cost to operate on supply networks whose voltage levels, connectors, or network configurations are not compatible with the connection of the rope-feed winch.Some examples of such adapters are explained below.

[0028] The invention is described in more detail below with reference to preferred embodiments and the accompanying figures. These figures show: Fig. 1 a schematic side view of a rope-through winch according to one embodiment; Fig. 2 a schematic wiring diagram of a rope-through winch according to one embodiment; Fig. 3 a schematic representation of a control system for a rope-through winch according to one embodiment; Fig. 4a a schematic representation of adapters for a rope-through winch according to one embodiment; Fig. 4b a schematic representation of a further embodiment of a primary side of an adapter according to Fig. 4a Fig. 4 shows a schematic representation of a further preferred embodiment of a primary side of an adapter according to Fig. 4a

[0029] For identical or similar elements, the same reference numerals are assigned in relation to the exemplary embodiments. Insofar as no explicit reference is given for a figure, reference is made to the explanations for the other figures.

[0030] The Fig. 1 Figure 20 shows a rope-through winch with a drive unit 10, wherein the drive unit 20 comprises a frequency converter 30 with a primary side for drawing current from a supply network and a secondary side for supplying an alternating voltage, an alternating current motor 40 for driving the rope-through winch 10 with variable speed ω 1, which is supplied with the alternating voltage by the frequency converter 30, a control unit 50, which is connected to the frequency converter 30 and the alternating current motor 40 for controlling the drive unit 20, and an output unit 60 with a second speed ω 2 for applying a driving force to a rope (not shown), which is coupled to the drive unit 20.

[0031] The output unit 60, with a variable speed ω2, is coupled to the drive unit 20 via a connecting device G, for example via a gearbox, so that these speeds have a gear ratio. In a further embodiment, the output unit 60 and the drive unit 20 are connected via a common flange or have a common shaft. In these cases, the gear ratio is essentially 1, and the speed ω1 of the drive unit 20 corresponds to the speed ω2 of the output unit 60.

[0032] To supply power to the cable winch, the drive unit 20 is coupled to the electrical supply network via a connection device 80, which is designed, for example, as an adapter 80, so that the cable winch 10 is energized for operation. The frequency converter 30 and the control unit 50 are designed as two parts.

[0033] The Fig. 2 Figure 1 shows the wiring of a rope-driven winch 10 according to one embodiment. The drive unit 20 has a frequency converter 30 with a DC link C, wherein the primary side of the frequency converter 32 has the three phases L1, L2, L3 for current input, which are connected to the three phases R, S, T of the power supply network 70 in the correct phase such that the nominal voltage of the electrical power supply network 70, preferably 230 V, is provided to the frequency converter 30 at the primary side 32. The frequency converter 30 is thus configured for operation on a conventional three-phase power supply network 70. The primary side 32, or the frequency converter 30, is further configured to be operated with an input voltage of at least 400 V.

[0034] The frequency converter 30 has a rectifying device 33 on the primary side and an inverter device 35 on the secondary side, these being coupled to each other via a DC intermediate circuit such that the frequency converter provides a preferred three-phase AC voltage UU , UV , UW on its secondary side 36, which is supplied to the AC motor 40 via the phases U, V, W in such a way that it can drive the output unit 60 in order to apply the driving force F to a rope 62 passing through the rope-running winch 10.

[0035] Furthermore, the drive unit 20 of the rope-through winch 10 has a control unit 50 which is connected to the frequency converter 30 and the AC motor 40 via lines S, E1, E2, wherein control signals are given to the frequency converter 30 via a line S and the AC motor 40 is excited via a line which consists of a forward conductor E1 and a return conductor E2.

[0036] In a particularly preferred embodiment, the frequency converter 30 and the control unit are essentially formed as a single unit, i.e., as a device 90, which is connected to the electrical supply network 70 via an adapter 80. For this purpose, the adapter 80 has a primary side on the network side and a secondary side for connection to the cable winch 10, in particular for connection to the frequency converter 30 and / or the control unit 50. The adapter is further configured to provide at least a single-phase nominal AC voltage of 230 V on the secondary side, and the supply network 70 has a nominal voltage of at least 50 V, preferably at least 100 V, more preferably at least 200 V, and particularly preferably at least 230 V.

[0037] The control unit 50 also has at least one voltage sensing device 52 and is configured to change, in particular reduce, the speed of the AC motor ω 1 when an undervoltage is detected. According to one embodiment, the means for voltage sensing 52 are arranged on the primary side 32 of the frequency converter 30 such that the voltage sensing device 52 can detect a voltage dip in the mains voltage of the supply network 33. The control unit 50 may also have a further voltage sensing device 52 that detects the motor voltage Uu, Uv, Uw on the secondary side 36 of the frequency converter 30.

[0038] Furthermore, the control unit has at least one current sensing device 56 and is configured to change, in particular reduce, the speed of the AC motor ω 1 when an overcurrent is detected. According to one embodiment, the current sensing means 56 are arranged on the secondary side 36 of the frequency converter such that the current sensing device 56 can detect an excessively high current in the AC motor. The control unit can also have further current sensing devices 56 on the primary side 32 of the frequency converter 30 that detect the supply current flowing into the frequency converter 30.

[0039] The control unit 50 is configured to adjust the speed of the AC motor ω1 in stages so that the undervoltage and / or overcurrent detected by means 62, 66 are taken into account in the power output of the drive unit 20, in particular so that in the event of a voltage dip, the speed of the drive unit ω1 and consequently the speed of the output unit ω2 is reduced so that the rope 62 running through the rope winch has a lower speed, in particular half its rated speed. In a particularly preferred embodiment, the rope 62 has a rated speed of 18 meters per minute, and the control unit is configured to halve the speed to 9 meters per minute.

[0040] The control unit 50 is therefore designed to change the speed of the AC motor ω 1 as a function of the detected undervoltage and / or overcurrent so that the electrical power requirement of the AC motor 40 decreases by the same amount as the AC voltage UR , US , UT supplied by the supply network 33 at the frequency converter 30.

[0041] The Fig. 3 Figure 1 shows a preferred control system for a rope-driven winch 10 according to one embodiment, wherein the frequency converter 30 and the control unit 50 are designed in a device 90 with three phases L1, L2, L3 for current consumption. The three phases L1, L2, L3 can be configured according to Fig. 2 to be connected to a power supply network (not shown). To prevent damage to the rope-feed winch 10, for example in the event of overcurrent, the rope-feed winch has an emergency stop switch 92, which is configured to disconnect the rope-feed winch 10 from the power supply network. In a preferred embodiment, this is done by means of the control unit 50, which has a control output A1 configured to actuate the emergency stop switch so that the rope-feed winch is disconnected from the power supply network. The rope-feed winch can also have a push button (not shown) for this purpose, which can be manually actuated by service personnel in the event of a fault to prevent damage to the rope-feed winch 10.

[0042] The frequency converter 30 has three phases U, V, W, by means of which the AC motor 40 of the rope winch is powered. The frequency converter 30 is further configured to be operated on a supply network with at least one phase. Preferably, the frequency converter is configured to be operated on a supply network with three phases.

[0043] Furthermore, the control unit 50 has two control outputs A10 and A11 which are connected to the positive conductor E1 and the negative conductor E2 such that the AC motor 40 is excited with a first excitation voltage so that the AC motor 40 has the speed of a first stage S1, thereby causing the rope-driven winch 10 to have a first speed, for example 18 meters per minute. The first stage S1 is selected by the control unit 50 by means of a first switch S1.

[0044] Furthermore, the control unit 50 has a control output A22. In the event of a detected undervoltage and / or overcurrent, the control unit switches the control inputs A11 and A22 so that the AC motor 40 is excited with a second excitation voltage, causing the AC motor 40 to operate at the speed of a second stage S2. This results in the rope winch operating at a second speed, for example, 9 meters per minute. The second stage S2 is selected by the control unit 50 using a second switch S2. Depending on the type of control, different switching states result for the switching logic. For example, for the first stage S1, the first switch S1 is closed and the second switch S2 is open, and for the second stage, the first switch S1 is open and the second switch S2 is closed. The control unit 50 is therefore configured to change the speed of the AC motor in steps between two stages S1 and S2.Preferably, the control unit is configured to change the speed of the AC motor so that the electrical power requirement of the AC motor 40 is halved or doubled. Optionally, the control unit 50 is configured to change the speed of the AC motor ω 1 in steps between four levels.

[0045] The control unit 50 also includes a control database 58, which is configured to provide pre-programmed control values ​​to the control unit 50, particularly depending on detected voltages and currents. The cable winch is thus configured to be programmed for specific supply networks and / or tasks so that it can be adapted to the winch's area of ​​application. The control unit optionally has a control voltage of 24 V. In a particularly preferred embodiment, the control voltage is 230 V.

[0046] The control unit 50 is therefore designed to change the speed of the AC motor n depending on the detected undervoltage and / or overcurrent, as determined by the voltage detection means and / or the current detection means, so that the electrical power requirement of the AC motor 40 decreases by the same amount as the AC voltage supplied by the mains supply at the frequency converter 30 or the device 90.

[0047] Furthermore, the control unit 50 has a control output A33, which is configured to reverse the direction of rotation of the AC motor 40. Control output A33 therefore has a potential that is opposite to the potentials of control outputs A11 and A22, such that the excitation current flowing through the AC motor reverses its direction. In one embodiment, the rope-driven winch 10 has two forward speeds and one reverse speed.

[0048] The device 90 also includes a protective device 94, which is configured to detect a faulty excitation current of the AC motor. This can be done, for example, by the current sensing means of the control unit. In the event of a faulty excitation current, the protective device trips and interrupts the excitation of the AC motor.

[0049] Furthermore, the device 90 has an electric brake 96 which can be controlled via the control outputs A40, A42, wherein the electric brake 96 is designed to brake the AC motor 40 and thus the rope-through winch 10.

[0050] The Fig. 4a Figure 1 shows a schematic representation of an adapter 80 of a rope-through winch 10 according to one embodiment.

[0051] Adapter 80 has a mains-side primary side 82 and a secondary side 84 for connection to the rope-driven winch, which are coupled to each other via a connecting element 86. The mains-side primary side 82 has the terminals L1, L2, L3, N, PE, so that the adapter 80 is configured to be connected to any power supply network, for example via plugs. The secondary side 84 has the terminals L1, L2 / N, PE, so that the secondary side is configured to be coupled to an AC motor 40 according to one embodiment. Furthermore, the adapter is configured to provide at least a single-phase nominal AC voltage of 230 V on the secondary side.

[0052] The Fig. 4b shows a schematic representation of another embodiment of a primary-side adapter according to Fig. 4a The primary side 82 has the connections L1, L3, PE, so that the adapter is set up to be connected to an equivalent mains connection.

[0053] The Fig. 4c shows a schematic representation of a further preferred embodiment of an adapter according to Fig. 4a The primary side 82 has the connections L1, N, PE, so that the adapter is set up to be connected to an equivalent mains connection.

Claims

1. Continuous cable winch (10) with a drive unit (20) and a output unit (60) for applying a drive force to a cable, which output unit is coupled to the drive unit (20), wherein the drive unit (20) comprises: - a frequency converter (30) with a primary side (32) for receiving current from a power grid (33) and a secondary side (36) for outputting an AC voltage (UU , UV , UW ), - an AC motor (40) for driving the continuous cable winch (10) at variable rotational speed (ω1), the motor being supplied with the AC voltage (Uu , Uv , UW ) by the frequency converter (30), characterized by - a control unit (50) connected to the frequency converter (30) and to the AC motor (40) for controlling the drive unit (20), wherein the control unit (50) is connected to the AC motor (40) via a forward conductor (E1) and a return conductor (E2), wherein - the control unit (50) is configured to change the rotational speed (ω1 ) of the AC motor (40) by means of the frequency converter (30).

2. Continuous cable winch according to claim 1, wherein - the control unit (50) comprises voltage detection means (52) and is configured to change, in particular to reduce, the rotational speed (ω1) of the AC motor when an undervoltage is detected.

3. Continuous cable winch according to claim 1 or 2, wherein - the control unit comprises current detecting means (56) and is configured to change, in particular to reduce, the rotational speed (ω1) of the AC motor when an overcurrent is detected.

4. Continuous cable winch according to any one of the preceding claims, wherein - the control unit (50) is configured to change the speed of the AC motor (ω1 ) stepwise, preferably in four stages, particularly preferred in two stages (S1 , S2 ).

5. Continuous cable winch according to any one of the preceding claims, wherein - the control unit (50) comprises a control database and the control database is configured to provide preprogrammed control values to the control unit (50), in particular depending on detected voltages and currents.

6. Continuous cable winch according to any one of the preceding claims, wherein - the control unit (50) is configured to change the rotational speed (ω1) of the AC motor in response to the detected undervoltage and / or the detected overcurrent in such a way that the electrical power requirement of the AC motor (40) decreases at the same rate as the AC voltage (UR, Us, UT) supplied by the power grid (33) at the frequency converter (30).

7. Continuous cable winch according to any one of the preceding claims, wherein - the control unit (50) is configured to halve and to double the electrical power requirement of the AC motor (40).

8. Continuous cable winch according to any of the preceding claims, wherein - the frequency converter (30) is configured to be operated on a power grid (33) having a number of phases, preferably in a range from one phase to three phases.

9. Continuous cable winch according to any one of the preceding claims, wherein - the frequency converter (30) and the control unit (50) are designed as an integrated device (90).

10. Continuous cable winch according to claim 6, wherein - the power grid (33) has a nominal voltage of at least 50V, preferably at least 100V, more preferably at least 200V, and particularly preferably at least 230V.

11. Continuous cable winch according to any one of the preceding claims, wherein - the AC motor (40) is configured to operate with a single-phase nominal AC voltage of 230 V.

12. Continuous cable winch according to any one of the preceding claims, wherein - the frequency converter (30) is configured to operate on a three-phase power grid (33) with at least 400 V.

13. Continuous cable winch according to any one of the preceding claims, wherein - the control voltage of the rectifier is 24 V, preferably 230 V.

14. Continuous cable winch according to any one of the preceding claims, wherein - the continuous cable winch has an adapter (80) with a primary grid side and a secondary side for connection to the continuous cable winch (10), and - the adapter is configured to provide at least a single-phase nominal AC voltage of 230 V on the secondary side.